Process of forming filaments for incandescent electric lamps



(No Model.)

I E. P. THOMPSON. PROCESS OF FORMING FILAMBNTS FOR INOANDESUBNT ELECTRICLAMPS.

No. 370,998. Patented Oct. 4, 1887.

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UNITED STATES PATENT, O FICE.

EDWARD P. THOMPSON, OF ELIZABETH, NEWV JERSEY.

PROCESS OF FORMING FILAMENTS FOR INCANDESCENT ELECTRIC LAMPS.

SPECIFICATION forming part. of Letters Patent No. 370,998, dated'octcber4, 1887.

Application tiled January 22. 1887. Serial No. 225,118.

To all whom it may concern:

Be it known that I, EDWARD P. THOMPSON, a citizen of the United States,residing in Elizabeth, in the county of Union and State of New Jersey,have invented certain new and useful Improvements in Processes ofForming Fila ments for Incandescent Electric Lamps, of which thefollowing is a specification.

The invention relates to a method of building up carbons by depositionfrom a hydrocarbon compound; and the object of the invention is toprovide a filament composed essentially or entirely of the deposit ofcarbon.

The invention consists, in general terms, in alternately depositingcarbon upon a basis of carbonized fiber and removing portions of thebasis or original carbon.

In carrying out the invention a filament of any suitable character isplaced in a suitable chamber, wherein a deposit of carbon may be madefrom a suitable hydrocarbon. After a certain deposit has been applied aportion of the original filament is removed in any suitable manner-as,for instance, by admitting heated sulphur, which will act upon thefilament carbon before attacking the deposited carbon, thus creatingpores in the filament. A second deposit is then made and the operationis repeated. In this manner the filament is alternatelyrendered ofincreased and decreased resistance, and essentially the whole of theoriginal carbon is removed and the filament is entirely composed ofdeposited carbon. The carbon of the filament yields more readily to theheated sulphur because it is combustible at a lower temperature than thedeposited carbon.

In the accompanying drawings, Figure 1 illustrates a method of buildingup the carbon by means of a hydrocarbon compound and burning out orremoving the original carbon filament by means of heated sulphur. Fig. 2illustrates a different method of treating the filaments for producingessentially the same results.

Referring to the figures, A represents a containingchamber of anysuitable character, in which is placed a filament, B. This filament ispreferably connected at its respective terminals with the respectivepoles of a generator, E, of any suitable character, whereby a (Nomodel.)

In carrying out the invention a deposit of 7 carbon is made from theatmosphere by bydrocarbon vapor introduced through the tube 0, thefilament B being heated at the same time by means of a current from thegenerator E. After a suitable deposit is made the by drocarbon isexhausted from the chamber A by means of the vacuum-pump, and afterwarda quantity of sulphur -vapor is introduced through the tube d. Thecurrent meanwhile isdiminished by means of a resistance, r, or in anyother suitable manner, so that the filament is heated only to a redheat, and the sulphur-vapor will attack the carbon of the originalfilament, forming a bisulphide of carbon and rendering the filament moreporous and of higher resistance. It may be necessary to graduate thecurrent during the time the sulphur is acting upon the filament. Thesulphur attacks the carbon of the orignal filament more readily than thedeposited carbon, and the former may be removed to a more or lessextent; without affecting the latter. The sulphur is then withdrawn fromthe chamber A, and the hydrocarbon vapor is then again introduced, andthe temperature of the filament is increased. This operation is repeateduntil practically all the original filament is removed and the resultantfilament is one composed essentially of the deposited carbon.

In Fig. 2 the process is illustrated as being carried out by means ofheated sulphur, in which the original carbon is removed by alternatelyplacing the same in a bath of heated sulphur and depositing carbon byplacing it ment is first placed in the sulphur-bath and then placed inthe depositing-chamber. In this figure, B represents the filament, asbefore, andcA the sulphur-bath, which is melted in any convenientmanner. filamentis placed in a carbon-depositing chamber, such asillustrated in Fig. 1, and the op eration is repeated until the requiredresult is obtained.

It is evident that it may be necessary to repeat the operation a greatmany times in order to render the process entirely satisfactory andperfect. It may not always be necessary to apply heated sulphur, but itmay be heated to only a red heat in the open air, and the oxygen of theatmosphere will attack the original filament.

instead of heating the filaments by means of a current, it may in someinstances be desired to place them in a furnace of any suitablecharacter, preferably a reverberatory furnace wherein oxygen isconstantly supplied, and this will secure the result in the mannerspecified in the preceding modification. The temperatu re of thefilament should be kept at only a red heat to prevent the depositedcarbon from consumption. The filaments are then mounted in avacuum-globe in the usual manner.

1 claim as my invention-- 1. The hereinbefore-described process of Fromthis bath the building up filaments of deposited carbon, which consistsin alternately depositing carbon upon a carboneore and removing portionsof the said core independently of the carbon de- 5 )OSlll.

1 2. The hereinbeforedescribed process of manufacturing incandescentelectric lamps, which consists in depositing carbon upon a core ofcarbonized fiber, removing portions of o such core by chemical action orcombustion independently of the carbon deposit-em, and mounting thefilaments in a vacuum-globe.

3. The hereinbefore-described process of forming filaments forincandescent electric J lamps, which consists in depositing carbon upona core throughout its length and alternately removing portions of suchcore independently of the carbon deposit.

4. The hereinbefore-dcscribed process of 30 building up filaments ofdeposited carbon, which consists in alternately depositing car bon upona carbon-core and removing portions ofsaid core by hearing in asulphurfluid.

In testimony whereof I have hereunto sub- 55 scribed my name this 21stday of January, A.

EDWARD P. THOMPSON.

Witnesses:

DANL. W. Enenoone, CHARLES A. TERRY.

